34825 datasheet(25/39 Pages) FREESCALE

25 / 39 page

VBUS

Removed

Clear

VBUS_DET bit

Clear

ATTACH bit

Set

ID_FLOAT bit

ID Float

Yes

Set

DETACH bit

Clear

ACTIVE bit

VBUS=5V

RID

Connected

Yes

Analog Integrated Circuit Device Data

Freescale Semiconductor

34825

FUNCTIONAL DEVICE OPERATION

LOGIC CONTROL FEATURES

Figure 18. The Detachment Detection Flow

LOGIC CONTROL FEATURES

RESET

HARDWARE RESET

The 34825 has three sources for hardware resetting the

IC. As the Figure 19 shows, the sources include the Power-

On-Reset caused by the rising VDD, a hardware reset

caused by the VDDIO input and a hardware reset using the

I2C bus lines. The Power-On-Reset is described earlier. The

reset caused by the VDDIO input or by the I2C bus lines

belongs to system resets.

The hardware reset condition using the I2C signals is

shown in Figure 20. When both the I2C_SCL and the

I2C_SDA have a negative pulse with time of tRSTI2C, a

hardware reset is generated. The result of the reset is same

as a Power-On-Reset.

The operating waveforms of the hardware reset using the

VDDIO pin are shown in Figure 21. The VDDIO detection has

a deglitch-time tVDDIODGT_F. A glitch on the VDDIO with

duration less than the deglitch time will be ignored. If the

pulse on the VDDIO lasts longer than the deglitch time, a

reset from the VDDIO is detected to generate a reset signal.

To effectively reset the 34825, the reset pulse from the

VDDIO needs be longer than the 150

μs minimum reset

pulse width given in the Dynamic Electrical Characteristics

table.

SOFTWARE RESET

In addition to the two hardware reset types, the system

reset has another reset source, the software reset by writing

‘1’ to the RESET bit in the Control register. The Reset bit will

be cleared to ‘0’ at once since it is of W/C type. The

consequence of the software reset is the same as the

hardware reset. All registers will be reset.

34825 Datasheet(PDF) 25 Page - Freescale Semiconductor, Inc

34825 Datasheet(HTML) 25 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

Datasheet Download

Link URL